1. Field of the Invention
The present invention relates to Digital Multimedia Broadcasting (DMB) service, and in particular, to a method and apparatus for smoothly providing terrestrial DMB service according to channel service areas by a DMB receiving terminal.
2. Description of the Related Art
Generally, broadcasting signals provided by a provider of digital broadcasting (e.g., terrestrial DMB such as Eureka-147 DMB) are transmitted within a frequency range allocated according to each broadcasting station. For example, in Korean DMB, six terrestrial broadcasting providers have been selected, in which each broadcasting station is allocated a frequency band of 2 MHz. In order to receive broadcasting signals transmitted through such six frequency bands, it is necessary to tune a receiver to the frequency band of a provider desired by the user. Thus, a receiver with only one tuner cannot receive signals transmitted through frequency bands other than a set frequency band and cannot check the reception sensitivity of a corresponding broadcasting channel.
Also, since remote nodes of each broadcasting station are allocated different frequency bands, a frequency band allocated to a terrestrial DMB for the Korean capital area, for example, is now unavailable for the same terrestrial DMB in a local area, and different frequency bands depending on areas must be used for the same broadcast program. As a result, like FM radio, whenever the user moves from one area to another area, it is necessary to search for a corresponding frequency band and to tune the receiver to the searched frequency band. Such a tuning operation is manually performed.
In FIG. 1, it can be understood that although the Korean terrestrial DMB uses frequency bands of CH7 to CH13, which are in a VHF band, the Korea National Capital Region area broadcasting currently being provided uses two frequency bands of CH8 and CH12, and different areas except for the National Capital Region area use frequency bands which can be secured according to each area. Here, FIG. 1 is a view illustrating the present status of terrestrial DMB channels selected according to service areas. Owing to such a frequency environment being different depending on each area, it is impossible to construct a Single Frequency Network (SFN) for nationwide service. Instead, a Multi-Frequency Network (MFN) using frequencies allocated according to areas is constructed.
However, since an Electric Program Guide (EPG) for the terrestrial DMB being currently provided is not provided, the user must make a channel information list about channels which can be received in a corresponding area, through a channel search by himself/herself. Such a channel information list includes a detailed frequency band, an ensemble ID and a service ID. The detailed frequency band may include three detailed areas of A, B and C, for example, 12A, 12B and 12C, according to each band. The ensemble ID represents a broadcasting station name, and the service ID represents a channel name. When searching for a channel under the MFN condition, the user cannot recognize the frequency band corresponding to each service area, so that the user must perform a channel search with respect to all the terrestrial DMB bands of CH7 to CH13. This results in searching even for unnecessary frequency bands, thereby requiring a long period of time for channel searching. When a channel search is performed with respect to all the terrestrial DMB bands, it takes about 40 seconds to one minute.
In addition, when a channel service area is changed while a DMB broadcast is being provided through the DMB service, a channel providing the DMB broadcast is changed according to the change of the channel service area, so that even the same DMB broadcast is interrupted.